Sintering machine



R. W. HYDE ET AL Sept. 3, 1940.

SINTERING MACHINE 2 Sheescs-Sheet l Filed Sept. 14, 1959 ,OEE

OYI w MHH m ww.. n R A DE R EB E w RR T SPt- 3 19404 JR. w. HYDE E-r AL.y 2,213,396

sINttEn-'iING AMACHINE Filed sept. 14. i939" zhsne'ggg-.sneet 2INVENTORS REED W. HYDE THEIR ATroRNEY.

Patented Sept.` 3, 1940 A UNITED. STATES 2,213,396 SINTERING MACHINEReed Hyde,

summit, N. J., and Robert nike,

Piedmont, Calif.

Application September 14,1939, Serial No. 294,810

3 Claims.

Our invention relates to a sintering machine or furnace of a travelinggrate '-type, burning lime or cement mixtures, in which the material tobe burned is carriedon a chain of travelingpallets and in which the heatfor burning the lime or cementl is supplied downwardly from a furnace orvcombustion chamber positioned above the chain of pallets.

In sintering machines of the above type, the hot prducts of combustionmay be drawn downwardly through the grates of the pallets by suc- .tionboxes placed in the pallets and sealed-to them. After the burning of thelime or cement is completed, cold air may be blown through the grate tochill the material and this may be done either in a part of the samefurnace or in a separate machine.

To obtain uniform burning of the lime and cement and thus to insure thatsome of the material will not` be under burnedl or over burned, theentrance of air between the edges of the tr'aveling pallets and thefurnace Wall or the Vescape of hot products of combustion should beprevented or minimized. This, however, presents the diiliculty that thefurnace walls and the pallet structure enclosed within the furnace aresubjected to the flame or hot products of combustion which are at theirmaximum temperature within the furnace and before entering or passinginto the charge of material on the grate. Sealing material subjected tothese temperatures or exposedto radiation, or to contact with the hotgases',

would rapidly deteriorate or become ineffective.

Our present invention provides a sealing means between the walls of thefurnace and the traveling pallets that is protected from excessive heator contactwith the flame or hot products of combustion.

In our invention the pallets are provided with upstanding side wallswhich extend Ato within a short distance of the lower or bottom edge ofthe side walls of the furnace, being spaced from the side walls just.suflcient to insure a clearance between the wall of the furnace and ofthe 'pallets at all times.

Preferably, the lower edge or bottom of the furnace wall is inclinedupwardlyand outwardly for a considerable distance from its innersurfaceor face and the side walls of the pallets are extended upwardly andoutwardly in closely spaced, and preferably parallel, relation to theupwardly and outwardly sloped bottom portionof the furnace wall. In thisway the lower partV of the furnace wall protects the upward and outwardextension of the pallet wall from direct radiation from the interior ofthe furnace and permits the youtward extension to remain relativelycool.

A sealing strip, made either of flexible metal or on the furnace wallnear its outer surface Aand bears against the wall of the pallet. It maybe either on the upper or lower surface of the outward extension and maybe held in place'respectively by the pressure or suction of the gaseswithin the furnace, or may be held in place by spring pressure.Preferably, the lower inner edge of the furnace wall extends downwardlysomewhat below the normal level of the charge on the pallets or gratesand thus also protects 'the outward extension from direct radiation or.from the ready circulation of hot gases.

The side walls of the pallets may be provided with a lining ofrefractory or heat-resistant material, the inner surface of which maybein appropriate alignment with the inner surface of the furnace wall sothat the outer wall portion of the pallets are spaced outwardly andprotected from the furnace heat, and may be either vertical or inclinedoutwardly.

With a vertical wall, the sealing strip attached to the lower part ofthe furnace preferably bears against the outer surface of the palletwall and the lower or bottom edge of the furnace wall may besubstantially horizontal.

The various features of our invention are illustrated by way of examplein the accompanying drawings in which Figs. 1, 2 and 3 are verticalcross-sections through a portion of a furnace wall and palletsembodying'various forms or modifications of our invention. Referringparticularly to Fig. 1 of the accompanying drawings, the charge materialvlll is supported on grate bars II or pallets I2 arranged' in acontinuous chain and supported by wheels or rollers I3 that run on atrack` I4. A succession of pallets I2 is provided in such close contactas to form a substantially continuous travel-- ing platform, at one endof which the material, to be acted on, such as raw cement mixture orlimestone, is supplied and on the other end of which the finished orburned product is delivered.

To supply heat for carrying von the action, which may be endothermic, asin the case 'of burned limestone, suitable fuel is burned in a furnaceI5 above the charge Il) and the hot products of combustion drawndownwardly therethrough and through the grate bars I I and palletstructure I2 into a suction box I6 below the chain of pallets. Thesuction box I6 is sealed to the lower part of the pallets with asuitable seal, such as the flexible strip In passing through the chargeI0 heat is absorbed from the hot products of combustion which are tionbox I6 at a much lower temperature. The

walls of the furnace I5 are subjected to the high or incandescenttemperature of the burning fuel The walls of the furnace extenddownwardly a short distance below the level of the top of the'charge Il!and a substantial distance above the grates II. To confine the charge IUon the grates of the pallet, the pallets are provided with side walls I8extending upwardly to within a short distance of the lower edge of thefurnace wall. They cannot'come in direct contact with the lower surfaceof the furnace wall as that would cause abrasion and destruction of thewalls.

To fill in the space between the upper edge of the pallet wall I8 andthe lower edge of the furnace wall I and provide an effective sealshielded from the high temperatures of the furnace, the lower surface oredge of the furnace wall l5 is inclined upwardly and outwardly as at I9and the pallet wall II! is provided with an upwardly and outwardlyinclined extension 20, the upper'surface of which is closely spaced fromthe surface I9.

The furnace wall I5 may be providedlwith a supporting structure orironwork 2l, and at the lower edge of this supporting structure there ismounted a sealing strip 22 which may be made of spring metal bearingdirectly on theupper surface of extension 20, and preferably providedwith a facing of flexible refractory material, such as a woven or otherform of asbestos sheet, or may consist of a flexible strip of asbestosor other heat-resisting material.

In the event that the furnace I5 is operated under a pressure slightlyabove atmospheric, the strip 22 might be of easily flexible materialheld against the surface 2l] only by the air or gas pressure.

It will be noted that radiation from the interior of the furnace is cutoif from the strip 22 both by the intervening charge Ill and by the factthat there is no direct or straight line path from the strip. 22 to theinterior of 'the furnace. The overlapping of the charge ID and the lowerpart of the wall I5 also serves to obstruct cir culation of gasesbetween the interior of the furnace and the space between the surfacelil and the extension and thus provides an insulating or dead air space.Accordingly, the outer part of the extension 2d and the sealing strip22, which are freely exposed to the outside atmosphere and protectedfrom the heat of the furnace, remain relatively cool.

In the modification shown in Fig. 2, the arrangement of p llets, thecharge, the furnace rvwalls and suction box are substantially the samewall. This has Vthe advantage, when the furnace is under reduced orsub-atmospheric pressure, of tending to draw the strip 22 into closeexible engagement with the surface of the extension 20.

In the modification shown in Fig. 3, the arrangement and relativeposition of the pallets I2, furnace wall I3 and suction box I6 issimilar' to that of Figs. 1 and 2. But the charge Il) need not comeabove the lower edge of the/furnace wall I5. In this case, the sidewallI B extends directly upwardly to a very short space or distance belowthe lower edge or bottom of the furnace wall I3 and is protected by arefractory liner 24, the inner surface of which slopes to approximatealignment with the wall I3 and which is of approximately the same heightas the depth of the charge IU; consequently the wall I3 is protected orinsulated from the full heat of the furnace gases and of the charge III,and being exposed to the outside atmosphere is relatively cool.

Moreover, it is spaced outwardly from the inn terior of the furnace walland protected by the portion of the wall I3 immediately above the liner2li. The space between the upper edge of the wall I8 and the lower edgeor bottom oi' the wall I3 is closed by means of a flexible sealing strip25 which is secured to the lower horizontal edge or bottom of the wallI3 and is bent or flexed to about 90 into a position. to lie againsttheouter vertical surface of the wall I8. The flexing of thestrp 25serves to hold it against and seal the wall "I3, this action being aidedby the suction within the furnace when the latter is run undersub-atmospheric pressure.

Through the above invention a sealing means is provided through a seriesof travelling pallets and the walls of the furnace positioned thereaboveand is protected against the hot gases and the radiant heat from withinthe furnace. The resiliency of the seal may thus be preserved anddistorting, due to changes in temperature, avoided.

What we claim is:

l. A sintering apparaus comprising a chain of travelling pallets, thecombination of a furnace having a wall extending vertically upward fromthe edge of said chain of pallets, each pallet of said chain having awall extending upwardly from the edge of said pallet below the loweredge of the inner surface of said furnace wall and thence inclinedoutwardly and upwardly, the

bottom of said furnace wall being inclined substantially parallel withsaid inclined extension, and a sealing strip mounted on said wall beyondsaid inclined extension and extending inwardly thereof and flexiblysealing against a surface of said inclined extension.

2. A sintering apparatus comprising a chain of traveling pallets, thecombination of a furnace having a wall extending vertically upward fromthe edge of said chain of pallets, each pallet of said chain having awall extending upwardly from the edge of said pallet below the loweredge of the inner surface of said furnace wall vand thence inclinedoutwardly and upwardly, the bottom of said furnace wall being inclinedsubstantially parallel with said inclined extension, and a sealing stripmounted on said wall beyond said inclined extension and extend inginwardly thereof and flexibly sealing the upper surface of said inclinedextension.

3. The apparatus of claim 1 inwhich said sealing strip has a yieldableresilient surface resistant to heat bearing against the surface of saidpallet.

REED W. HYDE. ROBERT D. PIKE.

